/*
 *  BUILD COMMAND:
 *    gcc -Wall -I/usr/local/ofed/include -O2 -o RDMA_RC_example -L/usr/local/ofed/lib64 -L/usr/local/ofed/lib -libverbs RDMA_RC_example.c
 *      
 */
/****************************************************************************
 **
 *
 *		RDMA Aware Networks Programming Example
 *
* This code demonstrates how to perform the following operations using the VPI Verbs API:
 *
 *		Send
 *		Receive
 *		RDMA Read
 *		RDMA Write
 *
 ****************************************************************************
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdint.h>
#include <inttypes.h>
#include <endian.h>
#include <byteswap.h>
#include <getopt.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <infiniband/verbs.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>

/* poll CQ timeout in millisec (2 seconds) */
#define MAX_POLL_CQ_TIMEOUT 2000
#define MSG "SEND operation"
#define RDMAMSGR "RDMA read operation"
#define RDMAMSGW "RDMA write operation"
#define MSG_SIZE (strlen(MSG)+1)

#if __BYTE_ORDER == __LITTLE_ENDIAN
static inline uint64_t htonll(uint64_t x) { return bswap_64(x);}
static inline uint64_t ntohll(uint64_t x) { return bswap_64(x);}
#elif __BYTE_ORDER == __BIG_ENDIAN
static inline uint64_t htonll(uint64_t x) { return x;}
static inline uint64_t ntohll(uint64_t x) { return x;}
#else
#error __BYTE_ORDER is neither __LITTLE_ENDIAN nor __BIG_ENDIAN
#endif

/* structure of test parameters */
struct config_t
{
        const char      *dev_name;
        char    *server_name;
        u_int32_t       tcp_port;
        int     ib_port;
        int     gid_idx;
};

/* structure to exchange data which is needed to connect the QPs */
struct cm_con_data_t
{
        uint64_t        addr;/* Buffer address */
        uint32_t        rkey;/* Remote key */
        uint32_t        qp_num; /* QP number */
        uint16_t        lid;    /* LID of the IB port */
        uint8_t gid[16];        /* gid */
} __attribute__ ((packed));

/* structure of system resources */
struct resources
{
        struct ibv_device_attr  device_attr;    /*device attributes */
        struct ibv_port_attr    port_attr;      /* IB port attributes */
        struct cm_con_data_t    remote_props;   /* values to connect to remote side */
        struct ibv_context      *ib_ctx;        /* device handle */
        struct ibv_pd   *pd;    /*pd handle */
        struct ibv_cq   *cq;
        struct ibv_qp   *qp;
        struct ibv_mr   *mr;
        char *buf;
        int     sock;
};

struct config_t config =
{
        NULL,   /* dev_name */
        NULL,   /* server_name */
        19875,  /* tcp_port */
        1,      /* ib_port */
        -1      /* gid_idx */
};

/****************************************************************************
 
   Socket operations

   For simplicity, the example program uses TCP sockets to exchange control informacion. If a TCP/IP stack/connection is not available, connection manager (CM) may be used to pass this information. Use of CM is beyond the scope of this example

****************************************************************************/

/****************************************************************************
 **
 * Function: sock_connect
 *
 * Input
 *	servername	URL of server to connect to (NULL for server mode)
 *	port		port of service
 *
 * Output
 *	none
 *
 * Returns
 *	socket (fd) on success, negative error code on failure
 *
 * Description
 * Connect a socket. If servername is specified a client connection will be initiated to the indicated server and port. Otherwise listen on the indicated port for an incoming connection.
 *
 ******************************************************************************/

static int sock_connect(const char *servername, int port)
{
        struct addrinfo *resolved_addr = NULL;
        struct addrinfo *iterator;
        char    service[6];
        int     sockfd = -1;
        int     listenfd = 0;
        int     tmp;
        struct addrinfo hints =
        {
                .ai_flags = AI_PASSIVE,
                .ai_family = AF_INET,
                .ai_socktype = SOCK_STREAM
        };

        if (sprintf(service, "%d", port) < 0)
                goto sock_connect_exit;
	
	/* Resolve DNS address, use sockfd as temp storage */
        sockfd = getaddrinfo(servername, service, &hints, &resolved_addr);
        if (sockfd < 0)
        {
                fprintf(stderr, "%s for %s:%d\n", gai_strerror(sockfd), servername, port);
                goto sock_connect_exit;
        }
	
	/* Search through results and find the one we want */
        for (iterator = resolved_addr; iterator ; iterator = iterator->ai_next)
        {
                sockfd = socket(iterator->ai_family, iterator->ai_socktype, iterator->ai_protocol);
                if (sockfd >= 0)
                {
                        if (servername)
			{
				/* Client mode. Initiate connection to remote */
                        	if((tmp=connect(sockfd, iterator->ai_addr, iterator->ai_addrlen)))
                        	{
                        	        fprintf(stdout, "failed connect \n");
                        	        close(sockfd);
                        	        sockfd = -1;
                        	}
			}
                        else
                        {

 	                       /* Server mode. Set up listening socket an accept a connection * */
                                listenfd = sockfd;
                                sockfd = -1;
                                if(bind(listenfd, iterator->ai_addr, iterator->ai_addrlen))
                                        goto sock_connect_exit;
                                listen(listenfd, 1);
                                sockfd = accept(listenfd, NULL, 0);
                        }
                }
        }
        sock_connect_exit:
                if(listenfd)
                        close(listenfd);
                if(resolved_addr)
                        freeaddrinfo(resolved_addr);
                if (sockfd < 0)
                {
                        if(servername)
        	                fprintf(stderr, "Couldn't connect to %s:%d\n", servername, port);
                        else
                        {
                                perror("server accept");
                                fprintf(stderr, "accept() failed\n");
                        }
                }
        return sockfd;
}

/****************************************************************************
 **
 * Function: sock_sync_data
 *
 * Input
 * 	sock		socket to transfer data on
 * 	xfer_size	size of data to transfer
 * 	local_data	pointer to data to be sent to remote
 *
 * Output
 *	remote_data	pointer to buffer to receive remote data
 *
 * Returns
 *	0 on success, negative error code on failure
 *
 * Description
 *	Sync data across a socket. The indicated local data will be sent to the remote. It will then wait for the remote to send its data back. It is assumed that the two sides are in sync and call this function in the proper order. Chaos will ensue if they are not. :)
 *
 * Also note this is a blocking function and will wait for the full data to be received from the remote.
 *
 ****************************************************************************/

int sock_sync_data(int sock, int xfer_size, char *local_data, char *remote_data)
{
        int     rc;
        int     read_bytes = 0;
        int     total_read_bytes = 0;

        rc = write(sock, local_data, xfer_size);
        if(rc < xfer_size)
                fprintf(stderr, "Failed writing data during sock_sync_data\n");
        else
        	rc = 0;

        while(!rc && total_read_bytes < xfer_size)
        {
                read_bytes = read(sock, remote_data, xfer_size);
                if(read_bytes > 0)
                        total_read_bytes += read_bytes;
                else
                	rc = read_bytes;
        }

        return rc;
}

/****************************************************************************
 **
   End of socket operations
 ****************************************************************************
 **/
/* poll_completion */
/****************************************************************************
 **
 * Function: poll_completion
 *
 * Input
 * 	res	pointer to resources structure
 *
 * Output
 *	none
 *
 * Returns
 *	0 on success, 1 on failure
 *
 * Description
 *	Poll the completion queue for a single event. This function will continue to poll the queue until MAX_POLL_CQ_TIMEOUT milliseconds have passed.
 *
 ****************************************************************************/

static int poll_completion(struct resources *res)
{
        struct ibv_wc   wc;
        unsigned long   start_time_msec;
        unsigned long   cur_time_msec;
        struct timeval  cur_time;
        int     poll_result;
        int     rc = 0;

	/* poll the completion for a while before giving up of doing it .. */
        gettimeofday(&cur_time, NULL);
        start_time_msec = (cur_time.tv_sec * 1000) + (cur_time.tv_usec / 1000);
        do
        {
                poll_result = ibv_poll_cq(res->cq, 1, &wc);
                gettimeofday(&cur_time, NULL);
                cur_time_msec = (cur_time.tv_sec * 1000) + (cur_time.tv_usec / 1000);
        } while ((poll_result == 0) && ((cur_time_msec - start_time_msec) < MAX_POLL_CQ_TIMEOUT));

        if(poll_result < 0)
        {
        	/* poll CQ failed */
                fprintf(stderr, "poll CQ failed\n");
                rc = 1;
        }
        else if (poll_result == 0)
        {
        	/* the CQ is empty */
        	fprintf(stderr, "completion wasn't found in the CQ after timeout\n");
        	rc = 1;
        }
        else
        {
        	/* CQE found */
                fprintf(stdout, "completion was found in CQ with status 0x%x\n", wc.status);
        	/* check the completion status (here we don't care about the completion opcode */
                if (wc.status != IBV_WC_SUCCESS)
                {
                        fprintf(stderr, "got bad completion with status:0x%x, vendor syndrome: 0x%x\n", wc.status, wc.vendor_err);
                        rc = 1;
                }
        }
        return rc;
}

/****************************************************************************
 **
 * Function: print_config
 *
 * Input
 *	none
 *
 * Output
 *	none
 *
 * Returns
 *	none
 *
 * Description
 *	Print out config information
 * * ******************************************************************************/

static void print_config(void)
{
        fprintf(stdout, " ------------------------------------------------\n");
        fprintf(stdout, " Device name : \"%s\"\n", config.dev_name);
        fprintf(stdout, " IB port : %u\n", config.ib_port);
        if (config.server_name)
                fprintf(stdout, " IP : %s\n", config.server_name);
        fprintf(stdout, " TCP port : %u\n", config.tcp_port);
        if (config.gid_idx >= 0)
                fprintf(stdout, " GID index : %u\n", config.gid_idx);
        fprintf(stdout," ------------------------------------------------\n\n");
}

/****************************************************************************
 **
 * Function: usage
 *
 * Input
 *	argv0		command line arguments
 *
 * Output
 * 	none
 *
 * Returns
 * 	none
 *
 * Description
 *	print a description of command line syntax
 * * ****************************************************************************
 **/

static void usage(const char *argv0)
{
        fprintf(stdout, "Usage:\n");
        fprintf(stdout, " %s start a server and wait for connection\n", argv0);
        fprintf(stdout, " %s <host> connect to server at <host>\n", argv0);
        fprintf(stdout, "\n");
        fprintf(stdout, "Options:\n");
        fprintf(stdout, " -p, --port <port> listen on/connect to port <port> (default 18515)\n");
        fprintf(stdout, " -d, --ib-dev <dev> use IB device <dev> (default first device found)\n");
        fprintf(stdout, " -i, --ib-port <port> use port <port> of IB device (default 1)\n");
        fprintf(stdout, " -g, --gid_idx <git index> gid index to be used in GRH (default not used)\n");
}

/****************************************************************************
 **
 * Function: post_receive
 *
 * Input
 *	res	pointer to resources structure
 *
 * Output
 *	none
 *
 * Returns
 *	0 on success, error code on failure
 * 
 * Description
 *
 ****************************************************************************
 **/

static int post_receive(struct resources *res)
{
        struct ibv_recv_wr      rr;
        struct ibv_sge  sge;
        struct ibv_recv_wr      *bad_wr;
        int     rc;

        /* prepare the scatter/gather entry */
        memset(&sge, 0, sizeof(sge));
        sge.addr = (uintptr_t)res->buf;
        sge.length = MSG_SIZE;
        sge.lkey = res->mr->lkey;

        /* prepare the receive work request */
        memset(&rr, 0, sizeof(rr));
        rr.next = NULL;
        rr.wr_id = 0;
        rr.sg_list = &sge;
        rr.num_sge = 1;

        /* post the Receive Request to the RQ */
        rc = ibv_post_recv(res->qp, &rr, &bad_wr);
        if (rc)
                fprintf(stderr, "failed to post RR\n");
        else
                fprintf(stdout, "Receive Request was posted\n");
        return rc;
}

/****************************************************************************
 **
 * Function: resources_init
 *
 * Input
 *	res	pointer to resources structure
 * 
 * Output
 * 	res	is initialized
 * 
 * Returns
 * 	none
 * 
 * Description
 * 	res is initialized to default values
 * * ****************************************************************************
 **/

static void resources_init(struct resources *res)
{
        memset(res, 0, sizeof *res);
        res->sock = -1;
}

/****************************************************************************
 **
 * Function: resources_create
 * 
 * Input
 * 	res	pointer to resources structure to be filled in
 * 
 * Output
 * 	res	filled in with resources
 * 
 * Returns
 * 	0 on success, 1 on failure
 * 
 * Description
 * 
 * This function creates and allocates all necessary system resources. These are stored in res.
 * * *****************************************************************************/

static int resources_create(struct resources *res)
{
        struct ibv_device **dev_list = NULL;
        struct ibv_qp_init_attr qp_init_attr;
        struct ibv_device *ib_dev = NULL;
        size_t  size;
        int     i;
        int     mr_flags = 0;
        int     cq_size = 0;
        int     num_devices;
        int     rc = 0;

        /* if client side */
        if (config.server_name)
        {
                res->sock = sock_connect(config.server_name, config.tcp_port);
                if (res->sock < 0)
                {
                        fprintf(stderr, "failed to establish TCP connection to server %s, port %d\n", config.server_name, config.tcp_port);
                        rc = -1;
                        goto resources_create_exit;
                }
        }
        else
        {
                fprintf(stdout, "waiting on port %d for TCP connection\n", config.tcp_port);
                res->sock = sock_connect(NULL, config.tcp_port);
                if (res->sock < 0)
                {
                        fprintf(stderr, "failed to establish TCP connection with client on port %d\n", config.tcp_port);
                        rc = -1;
                        goto resources_create_exit;
                }
        }
        fprintf(stdout, "TCP connection was established\n");
        fprintf(stdout, "searching for IB devices in host\n");

        /* get device names in the system */
        dev_list = ibv_get_device_list(&num_devices);
        if (!dev_list)
        {
                fprintf(stderr, "failed to get IB devices list\n");
		rc = 1;
                goto resources_create_exit;
        }

        /* if there isn't any IB device in host */
        if (!num_devices)
        {
                fprintf(stderr, "found %d device(s)\n", num_devices);
                rc = 1;
                goto resources_create_exit;
        }

        fprintf(stdout, "found %d device(s)\n", num_devices);

        /* search for the specific device we want to work with */
        for (i = 0; i < num_devices; i ++)
        {
                if(!config.dev_name)
                {
                        config.dev_name = strdup(ibv_get_device_name(dev_list[i]));
                        fprintf(stdout, "device not specified, using first one found: %s\n", config.dev_name);
                }
                if (!strcmp(ibv_get_device_name(dev_list[i]), config.dev_name))
                {
                        ib_dev = dev_list[i];
                        break;
                }
        }

        /* if the device wasn't found in host */
        if (!ib_dev)
        {
                fprintf(stderr, "IB device %s wasn't found\n", config.dev_name);
                rc = 1;
                goto resources_create_exit;
        }

        /* get device handle */
        res->ib_ctx = ibv_open_device(ib_dev);
        if (!res->ib_ctx)
        {
                fprintf(stderr, "failed to open device %s\n", config.dev_name);
                rc = 1;
                goto resources_create_exit;
        }

        /* We are now done with device list, free it */
	ibv_free_device_list(dev_list);
        dev_list = NULL;
        ib_dev = NULL;

        /* query port properties */
        if (ibv_query_port(res->ib_ctx, config.ib_port, &res->port_attr))
        {
                fprintf(stderr, "ibv_query_port on port %u failed\n", config.ib_port);
                rc = 1;
                goto resources_create_exit;
        }

        /* allocate Protection Domain */
        res->pd = ibv_alloc_pd(res->ib_ctx);
        if (!res->pd)
        {
                fprintf(stderr, "ibv_alloc_pd failed\n");
                rc = 1;
                goto resources_create_exit;
        }

        /* each side will send only one WR, so Completion Queue with 1 entry is enough */
        cq_size = 1;
        res->cq = ibv_create_cq(res->ib_ctx, cq_size, NULL, NULL, 0);
        if (!res->cq)
        {
                fprintf(stderr, "failed to create CQ with %u entries\n", cq_size);
                rc = 1;
                goto resources_create_exit;
        }

        /* allocate the memory buffer that will hold the data */
        size = MSG_SIZE;
        res->buf = (char *) malloc(size);
        if (!res->buf )
        {
                fprintf(stderr, "failed to malloc %Zu bytes to memory buffer\n",size);
                rc = 1;
                goto resources_create_exit;
        }
        memset(res->buf, 0 , size);

        /* only in the server side put the message in the memory buffer */
        if (!config.server_name)
        {
                strcpy(res->buf, MSG);
                fprintf(stdout, "going to send the message: '%s'\n", res->buf);
        }
        else
                memset(res->buf, 0, size);

        /* register the memory buffer */
        mr_flags = IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_READ |
        IBV_ACCESS_REMOTE_WRITE ;
	res->mr = ibv_reg_mr(res->pd, res->buf, size, mr_flags);
        if (!res->mr)
        {
                fprintf(stderr, "ibv_reg_mr failed with mr_flags=0x%x\n", mr_flags);
                rc = 1;
                goto resources_create_exit;
        }
        fprintf(stdout, "MR was registered with addr=%p, lkey=0x%x, rkey=%x, flags=%x\n", res->buf, res->mr->lkey, res->mr->rkey, mr_flags);

        /* create the Queue Pair */
        memset(&qp_init_attr, 0, sizeof(qp_init_attr));
        qp_init_attr.qp_type = IBV_QPT_RC;
        qp_init_attr.sq_sig_all = 1;
        qp_init_attr.send_cq = res->cq;
        qp_init_attr.recv_cq = res->cq;
        qp_init_attr.cap.max_send_wr = 1;
        qp_init_attr.cap.max_recv_wr = 1;
        qp_init_attr.cap.max_send_sge = 1;
        qp_init_attr.cap.max_recv_sge = 1;
        res->qp = ibv_create_qp(res->pd, &qp_init_attr);
        if (!res->qp)
        {
                fprintf(stderr, "failed to create QP\n");
                rc = 1;
                goto resources_create_exit;
        }
        fprintf(stdout, "QP was created, QP number=0x%x\n", res->qp->qp_num);

        resources_create_exit:
                if(rc)
                {
			fprintf(stdout, "--------------------------------------resources create exit");
                /* Error encountered, cleanup */
                        if(res->qp)
                        {
                                ibv_destroy_qp(res->qp);
                                res->qp = NULL;
                        }
                        if(res->mr)
                        {
                                ibv_dereg_mr(res->mr);
                                res->mr = NULL;
                        }
                        if(res->buf)
                        {
                                free(res->buf);
                                res->buf = NULL;
                        }
                        if(res->cq)
                        {
                                ibv_destroy_cq(res->cq);
                                res->cq = NULL;
                        }
                        if(res->pd)
			{
                                ibv_dealloc_pd(res->pd);
                                res->pd = NULL;
                        }
                        if(res->ib_ctx)
                        {
                                ibv_close_device(res->ib_ctx);
                                res->ib_ctx = NULL;
                        }
                        if(dev_list)
                        {
                                ibv_free_device_list(dev_list);
                                dev_list = NULL;
                        }
                        if (res->sock >= 0)
                        {
                                if (close(res->sock))
                                fprintf(stderr, "failed to close socket\n");
                        res->sock = -1;
                        }
                }
        return rc;
}

/****************************************************************************
 **
 * Function: post_send
 *
 * Input
 *	res	pointer to resources structure
 *	opcode	IBV_WR_SEND, IBV_WR_RDMA_READ or IBV_WR_RDMA_WRITE
 *
 * Output
 *	none
 *
 * Returns
 *	0 on success, error code on failure
 *
 * Description
 * 
 * 	This function will create and post a send work request
 ****************************************************************************
 **/

static int post_send(struct resources *res, int opcode)
{
        struct ibv_send_wr      sr;
        struct ibv_sge  sge;
        struct ibv_send_wr      *bad_wr = NULL;
        int     rc;

        /* prepare the scatter/gather entry */
        memset(&sge, 0, sizeof(sge));
        
	sge.addr = (uintptr_t)res->buf;
        sge.length = MSG_SIZE;
        sge.lkey = res->mr->lkey;

        /* prepare the send work request */
        memset(&sr, 0, sizeof(sr));
        
	sr.next = NULL;
        sr.wr_id = 0;
        sr.sg_list = &sge;
        sr.num_sge = 1;
        sr.opcode = opcode;
        sr.send_flags = IBV_SEND_SIGNALED;
        
	if(opcode != IBV_WR_SEND)
        {
                sr.wr.rdma.remote_addr = res->remote_props.addr;
                sr.wr.rdma.rkey = res->remote_props.rkey;
        }

        /* there is a Receive Request in the responder side, so we won't get any into RNR flow */
        rc = ibv_post_send(res->qp, &sr, &bad_wr);
        if (rc)
                fprintf(stderr, "failed to post SR\n");
        else
        {
                switch(opcode)
                {
                        case IBV_WR_SEND:
                                fprintf(stdout, "Send Request was posted\n");
                                break;
                        case IBV_WR_RDMA_READ:
                                fprintf(stdout, "RDMA Read Request was posted\n");
                                break;
                        case IBV_WR_RDMA_WRITE:
                                fprintf(stdout, "RDMA Write Request was posted\n");
                                break;
                        default:
                                fprintf(stdout, "Unknown Request was posted\n");
                                break;
                }
        }
        return rc;
}

/****************************************************************************
 **
 * Function: modify_qp_to_init
 * 
 * Input
 * 	qp	QP to transition
 * 
 * Output
 *	none
 *
 * Returns
 * 	0 on success, ibv_modify_qp failure code on failure
 * 
 * Description
 * 	Transition a QP from the RESET to INIT state
 * * ****************************************************************************
 **/

static int modify_qp_to_init(struct ibv_qp *qp)
{
        struct ibv_qp_attr attr;
        int     flags;
        int     rc;
        memset(&attr, 0, sizeof(attr));
        attr.qp_state = IBV_QPS_INIT;
        attr.port_num = config.ib_port;
        attr.pkey_index = 0;
        attr.qp_access_flags = IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_READ | IBV_ACCESS_REMOTE_WRITE;
        flags = IBV_QP_STATE | IBV_QP_PKEY_INDEX | IBV_QP_PORT | IBV_QP_ACCESS_FLAGS;

        rc = ibv_modify_qp(qp, &attr, flags);
        if (rc)
                fprintf(stderr, "failed to modify QP state to INIT\n");
        return rc;
}

/****************************************************************************
 **
 * Function: modify_qp_to_rtr
 * 
 * Input
 * 	qp		QP to transition
 * 	remote_qpn	remote QP number
 * 	dlid		destination LID
 * 	dgid		destination GID (mandatory for RoCEE)
 * 
 * Output
 * 	none
 * 
 * Returns
 * 	0 on success, ibv_modify_qp failure code on failure
 * 
 * Description
 * 	Transition a QP from the INIT to RTR state, using the specified QP number
 * * ****************************************************************************
 **/

static int modify_qp_to_rtr(struct ibv_qp *qp, uint32_t remote_qpn, uint16_t dlid, uint8_t *dgid)
{
        struct ibv_qp_attr      attr;
        int     flags;
        int     rc;

        memset(&attr, 0, sizeof(attr));
        attr.qp_state = IBV_QPS_RTR;
        attr.path_mtu = IBV_MTU_256;
        attr.dest_qp_num = remote_qpn;
        attr.rq_psn = 0;
        attr.max_dest_rd_atomic = 1;
        attr.min_rnr_timer = 0x12;
        attr.ah_attr.is_global = 0;
        attr.ah_attr.dlid = dlid;
        attr.ah_attr.sl = 0;
        attr.ah_attr.src_path_bits = 0;
        attr.ah_attr.port_num = config.ib_port;
        if (config.gid_idx >= 0)
        {
                attr.ah_attr.is_global = 1;
                attr.ah_attr.port_num = 1;
                memcpy(&attr.ah_attr.grh.dgid, dgid, 16);
                attr.ah_attr.grh.flow_label = 0;
                attr.ah_attr.grh.hop_limit = 1;
                attr.ah_attr.grh.sgid_index = config.gid_idx;
                attr.ah_attr.grh.traffic_class = 0;
        }
        flags = IBV_QP_STATE | IBV_QP_AV | IBV_QP_PATH_MTU | IBV_QP_DEST_QPN | IBV_QP_RQ_PSN | IBV_QP_MAX_DEST_RD_ATOMIC | IBV_QP_MIN_RNR_TIMER;
        rc = ibv_modify_qp(qp, &attr, flags);
        if (rc)
                fprintf(stderr, "failed to modify QP state to RTR\n");
        return rc;
}

/****************************************************************************
 **
 * Function: modify_qp_to_rts
 * 
 * Input
 * 	qp	QP to transition
 * 
 * Output
 * 	none
 * 
 * Returns
 * 	0 on success, ibv_modify_qp failure code on failure
 * 
 * Description
 * 	Transition a QP from the RTR to RTS state
 ****************************************************************************
 **/

static int modify_qp_to_rts(struct ibv_qp *qp)
{
        struct ibv_qp_attr attr;
        int     flags;
        int     rc;

        memset(&attr, 0, sizeof(attr));
        attr.qp_state = IBV_QPS_RTS;
        attr.timeout = 0x12;
        attr.retry_cnt = 6;
        attr.rnr_retry = 0;
        attr.sq_psn = 0;
        attr.max_rd_atomic = 1;

        flags = IBV_QP_STATE | IBV_QP_TIMEOUT | IBV_QP_RETRY_CNT | IBV_QP_RNR_RETRY | IBV_QP_SQ_PSN | IBV_QP_MAX_QP_RD_ATOMIC;
        rc = ibv_modify_qp(qp, &attr, flags);
        if (rc)
                fprintf(stderr, "failed to modify QP state to RTS\n");
        return rc;
}

/****************************************************************************
 **
 * Function: connect_qp
 * 
 * Input
 * 	res	pointer to resources structure
 * 
 * Output
 * 	none
 * 
 * Returns
 * 	0 on success, error code on failure
 * 
 * Description
 * 	Connect the QP. Transition the server side to RTR, sender side to RTS
 ****************************************************************************
 **/

static int connect_qp(struct resources *res)
{
        struct cm_con_data_t    local_con_data;
        struct cm_con_data_t    remote_con_data;
        struct cm_con_data_t    tmp_con_data;
        int rc = 0;
        char temp_char;
        union ibv_gid   my_gid;

        if (config.gid_idx >= 0)
        {
                rc = ibv_query_gid(res->ib_ctx, config.ib_port, config.gid_idx, &my_gid);
                if (rc)
                {
                        fprintf(stderr, "could not get gid for port %d, index %d\n", config.ib_port, config.gid_idx);
                        return rc;
                }
        } else
                memset(&my_gid, 0, sizeof my_gid);

        /* exchange using TCP sockets info required to connect QPs */
        local_con_data.addr = htonll((uintptr_t)res->buf);
        local_con_data.rkey = htonl(res->mr->rkey);
        local_con_data.qp_num = htonl(res->qp->qp_num);
        local_con_data.lid = htons(res->port_attr.lid);
        memcpy(local_con_data.gid, &my_gid, 16);
        fprintf(stdout, "\nLocal LID = 0x%x\n", res->port_attr.lid);

        if (sock_sync_data(res->sock, sizeof(struct cm_con_data_t), (char *) &local_con_data, (char *) &tmp_con_data) < 0)
        {
                fprintf(stderr, "failed to exchange connection data between sides\n");
                rc = 1;
                goto connect_qp_exit;
        }
        remote_con_data.addr = ntohll(tmp_con_data.addr);
        remote_con_data.rkey = ntohl(tmp_con_data.rkey);
        remote_con_data.qp_num = ntohl(tmp_con_data.qp_num);
        remote_con_data.lid = ntohs(tmp_con_data.lid);
        memcpy(remote_con_data.gid, tmp_con_data.gid, 16);

        /* save the remote side attributes, we will need it for the post SR */
        res->remote_props = remote_con_data;
        fprintf(stdout, "Remote address = 0x%"PRIx64"\n", remote_con_data.addr);
        fprintf(stdout, "Remote rkey = 0x%x\n", remote_con_data.rkey);
	fprintf(stdout, "Remote QP number = 0x%x\n", remote_con_data.qp_num);
        fprintf(stdout, "Remote LID = 0x%x\n", remote_con_data.lid);

        if (config.gid_idx >= 0)
        {
	        uint8_t *p = remote_con_data.gid;
	        fprintf(stdout,"Remote GID = %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n", p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
        }

        /* modify the QP to init */
        rc = modify_qp_to_init(res->qp);
        if (rc)
        {
                fprintf(stderr, "change QP state to INIT failed\n");
                goto connect_qp_exit;
        }

        /* let the client post RR to be prepared for incoming messages */
        if (config.server_name)
        {
                rc = post_receive(res);
                if (rc)
                {
                        fprintf(stderr, "failed to post RR\n");
                        goto connect_qp_exit;
                }
        }

	/* modify the QP of both server and client to RTR */
	rc = modify_qp_to_rtr(res->qp, remote_con_data.qp_num, remote_con_data.lid, remote_con_data.gid);
        if (rc)
        {
                fprintf(stderr, "failed to modify QP state to RTR\n");
                goto connect_qp_exit;
        }

	/* modify the QP of server to RTS */ 
        if (!config.server_name)
	{
		rc = modify_qp_to_rts(res->qp);
	        if (rc)
	        {
	                fprintf(stderr, "failed to modify QP state to RTS\n");
	                goto connect_qp_exit;
	        }
		fprintf(stdout, "QP state was change to RTS\n");
	}

        /* sync to make sure that both sides are in states that they can connect to prevent packet loose */
        if (sock_sync_data(res->sock, 1, "Q", &temp_char)) /* just send a dummy char back and forth */
        {
                fprintf(stderr, "sync error after QPs are were moved to RTS\n");
                rc = 1;
        }

        connect_qp_exit:
                return rc;
}

/****************************************************************************
 **
 * Function: resources_destroy
 * 
 * Input
 * 	res	pointer to resources structure
 * 
 * Output
 *	none
 * 
 * Returns
 * 	0 on success, 1 on failure
 * 
 * Description
 * 	Cleanup and deallocate all resources used
 ****************************************************************************
 **/

static int resources_destroy(struct resources *res)
{
        int rc = 0;
        if (res->qp)
                if (ibv_destroy_qp(res->qp))
                {
                        fprintf(stderr, "failed to destroy QP\n");
                        rc = 1;
                }

        if (res->mr)
                if (ibv_dereg_mr(res->mr))
                {
                        fprintf(stderr, "failed to deregister MR\n");
                        rc = 1;
                }

        if (res->buf)
                free(res->buf);

        if (res->cq)
                if (ibv_destroy_cq(res->cq))
                {
                        fprintf(stderr, "failed to destroy CQ\n");
                        rc = 1;
                }

        if (res->pd)
                if (ibv_dealloc_pd(res->pd))
                {
                        fprintf(stderr, "failed to deallocate PD\n");
                        rc = 1;
                }

        if (res->ib_ctx)
		if (ibv_close_device(res->ib_ctx))
                {
                        fprintf(stderr, "failed to close device context\n");
                        rc = 1;
                }

        if (res->sock >= 0)
                if (close(res->sock))
                {
                        fprintf(stderr, "failed to close socket\n");
                        rc = 1;
                }

        return rc;
}

/****************************************************************************
 **
 * Function: main
 * 
 * Input
 * 	argc	number of items in argv
 * 	argv	command line parameters
 * 
 * Output
 * 	none
 * 
 * Returns
 * 	0 on success, 1 on failure
 * 
 * Description
 * 	Main program code
 * * *****************************************************************************/

int main(int argc, char *argv[])
{
        struct resources        res;
        int     rc = 1;
        char    temp_char;

        /* parse the command line parameters */
        while (1)
        {
                int c;
                static struct option long_options[] =
                {
                        {.name = "port", .has_arg = 1, .val = 'p' },
                        {.name = "ib-dev", .has_arg = 1, .val = 'd' },
                        {.name = "ib-port", .has_arg = 1, .val = 'i' },
                        {.name = "gid-idx", .has_arg = 1, .val = 'g' },
                        {.name = NULL, .has_arg = 0, .val = '\0'}
                };

                c = getopt_long(argc, argv, "p:d:i:g:", long_options, NULL);
                if (c == -1)
                        break;

                switch (c)
                {
                        case 'p':
                                config.tcp_port = strtoul(optarg, NULL, 0);
                                break;

                        case 'd':
                                config.dev_name = strdup(optarg);
                                break;

                        case 'i':
                                config.ib_port = strtoul(optarg, NULL, 0);
                                if (config.ib_port < 0)
                                {
                                        usage(argv[0]);
                                        return 1;
                                }
                                break;

                        case 'g':
                                config.gid_idx = strtoul(optarg, NULL, 0);
                                if (config.gid_idx < 0)
                                {
                                        usage(argv[0]);
                                        return 1;
                                }
                                break;

                        default:
                                usage(argv[0]);
                                return 1;
                }
        }

	 /* parse the last parameter (if exists) as the server name */
        if (optind == argc - 1)
                config.server_name = argv[optind];
        else if (optind < argc)
        {
                usage(argv[0]);
                return 1;
        }
	
	/* print the used parameters for info*/
        print_config();	

	/* init all of the resources, so cleanup will be easy */
        resources_init(&res);

	/* create resources before using them */
        if (resources_create(&res))
        {
                fprintf(stderr, "failed to create resources\n");
                goto main_exit;
        }

	/* connect the QPs */
        if (connect_qp(&res))
        {
                fprintf(stderr, "failed to connect QPs\n");
                goto main_exit;
        }

	/* let the server post the sr */
        if (!config.server_name)
                if (post_send(&res, IBV_WR_SEND))
                {
                        fprintf(stderr, "failed to post sr\n");
                        goto main_exit;
                }

	/* in both sides we expect to get a completion */
        if (poll_completion(&res))
        {
                fprintf(stderr, "poll completion failed\n");
                goto main_exit;
        }

	/* after polling the completion we have the message in the client buffer too */
	if (config.server_name)
		fprintf(stdout, "Message is: '%s'\n", res.buf);
	else
	{
		/* setup server buffer with read message */
		strcpy(res.buf, RDMAMSGR);
	}

	/* Sync so we are sure server side has data ready before client tries to read it */
	if (sock_sync_data(res.sock, 1, "R", &temp_char)) /* just send a dummy char back and forth */
	{
		fprintf(stderr, "sync error before RDMA ops\n");
		rc = 1;
		goto main_exit;
	}

	/* Now the client performs an RDMA read and then write on server. Note that the server has no idea these events have occured */
	if (config.server_name)
	{
		/* First we read contens of server's buffer */
		if (post_send(&res, IBV_WR_RDMA_READ))
		{
			fprintf(stderr, "failed to post SR 2\n");
			rc = 1;
			goto main_exit;
		}
	
		if (poll_completion(&res))
		{
			fprintf(stderr, "poll completion failed 2\n");
			rc = 1;
			goto main_exit;	
		}

		fprintf(stdout, "Contents of server's buffer: '%s'\n", res.buf);

		/* Now we replace what's in the server's buffer */
		strcpy(res.buf, RDMAMSGW);
			
		fprintf(stdout, "Now replacing it with: '%s'\n", res.buf);

		if (post_send(&res, IBV_WR_RDMA_WRITE))
		{
			fprintf(stderr, "failed to post SR 3\n");
			rc = 1;
			goto main_exit;
		}
	
		if (poll_completion(&res))
		{
			fprintf(stderr, "poll completion failed 3\n");
			rc = 1;
			goto main_exit;
		}
	}

	/* Sync so server will know that client is done mucking with its memory */	
	if (sock_sync_data(res.sock, 1, "W", &temp_char)) /* just send a dummy char back and forth */
	{
		fprintf(stderr, "sync error after RDMA ops\n");
		rc = 1;
		goto main_exit;
	}

	if(!config.server_name)
		fprintf(stdout, "Contents of server buffer: '%s'\n", res.buf);
	rc = 0;
	
	main_exit:
		if (resources_destroy(&res))
        	{
        	        fprintf(stderr, "failed to destroy resources\n");
        	        rc = 1;
        	}

		if(config.dev_name)
			free((char *) config.dev_name);
		fprintf(stdout, "\ntest result is %d\n", rc);
	
	return rc;
}
